Detection of canine intestinal allograft rejection by in vivo electrophysiologic monitoring1

The aim of this study was to evaluate the significance of in vivo measurements of electrophysiologic parameters for the detection of canine small bowel (SB) allo-graft rejection. In dogs of group I (n=17) a heterotopic SB autotransplantation was performed. Dogs of group II (n=8) received a heterotopic SB allograft in a fully mismatched donor-recipient combination. No immune-suppression was given. All grafts were monitored regularly by in vivo measurements of transepithelial potential differences (PDs) and by biopsies of the grafts. The overall technical failure rate was 36% caused by thrombosis at the vascular anastomosis in most cases. All successful autografts survived the experimental period and showed physiologic PD responses after stimulation by both a theophylline solution and a glucose solution. The successful allografts survived 5.5±0.2 days (mean ± SEM); the transepithelial PDs showed normal responses at postoperative day 3, but showed decreased responses at day 5 (P<0.05) and reversed responses at day 6 (P<0.05). The diminished PD responses correlated well with the onset of histologic alterations characteristic of rejection. This study demonstrates that serial monitoring of transepithelial PD responses is a non- invasive method to detect acute SB allograft rejection.